Popular Science Monthly/Volume 3/September 1873/The Glass-Sponges
By Rev. SAMUEL LOCKWOOD, Ph. D.
Hyalonema Lusitanicum, the Glass-rope Sponge. Half the natural size. The rush-like threads at the bottom form a twisted rope terminating in the teat-like projection at the top, where it is covered with fine sponge. This coil is the Glass-Rope. The sheath, or incrustation of little starry warts, is the work of a polyp, known as the Palythoa fatua. The conical head is a mass of sponge once called Carteria.
"Beating time, time, time,
In a sort of Runic rhyme."
The beating of each lash is doubtless downward, that is, inward; the effect of which is, a vacuum above, into which the water presses through the external pore. A second result of this downward beating of the cilia from a myriad of cells is, the impulsion of the passing water through the ramifications leading to the oscula. Thus the running of the waters is the sponge's ancient "Runic rhyme." Every sponge, then, has a very complete aquiferous system: its conduits at, the entrance of and along which the busy one-lashed cells occupy themselves forcing the water along; and the oscula, which may be likened to the outlets of sewers. During this circulation of the fluid through the living mass, the sarcode obtains its nourishment, and the skeleton its growth by a sort of absorption, or what is known to the physiologist as endosmotic action of the cells. We have then mentioned above three clearly specialized functions, as represented respectively by the inhalant pores, the exhalant oscula, and the uniciliated cells. And it is certainly a matter of prime importance that each cell should have this single lash. In fact, it raises it to the rank of a pacha with one tail, in a community where all are pachas of this dignity, and each one a commissioner of the water department, and a commissary of subsistence. "Both the oscula and pores can be closed at the will of the animal; but the oscula are permanent apertures; whereas, the pores are not constant, but can be formed afresh whenever and wherever required."
The sponges are the active eliminators of the salts of the ocean. In a large laboratory certain substances are kept in solution, so as to be ready to the chemist's hands. Nature's grand laboratory is the sea. There her little economic chemists are ceaselessly busy extracting, and putting into solid forms, the various mineral substances held in solution. Thus the coral polyps eliminate the carbonate of lime with which to build their beautiful structures. And the Alcyonarian polyp in this way builds up the delicate sea-fan, with its skeleton of keratose, or horn-like substance. And so is it with the sponges. They, too, are elaborators of the mineral treasures of the sea. Hence it has been attempted to group them upon considerations of their special building propensities. In this way the toilet-sponges, and, in general, those of commerce, which all affect horn, or keratose, in the structure of their skeletons, would be grouped together as the Keratosa; while those which choose lime would be called Calcarea; and those which build up with silex would be known as the Silicea. We have mentioned these groups in their order of rank. The highest is the vitreous, or glass-sponge, with which we are directly concerned.
In the recent deep-sea dredging, so charmingly described in Dr. Wyville Thompson's new book, "The Depths of the Sea," an account is given of the obtaining in British waters, at the depth of 30,000 feet(!), specimens of the Hyalonema, the famous Glass-Rope Sponge. It had been previously obtained from the coasts of Portugal, when the news astonished naturalists, as previously it had only been known as coming from Japan. It is, indeed, a wonderful object. We once saw a specimen in the cabinet of a learned institution. The professor pronounced it a coil of Japanese spun glass. "No," said another savant, "it is a plant." And at that time both were excusable, for even Ehrenberg had looked upon it as "an artificial product of Japanese industry." That is to say, the great microscopist regarded the object as an ingenious imposition, consisting of natural products artfully put together. Let the reader carefully inspect the cut of Hyalonema, Fig. 1, which we have taken from Dr. Thompson's book, and then let us attempt a description.
Suppose we should take a skein of smooth, compactly-spun, glossy-white silk, about twenty-four inches in length, and, cutting the ends off evenly at one extremity, should give it a loose twist along the entire length, except some six inches at the bottom, which we leave, so to speak, frayed, or shaken out. Then around the other end of this silken cord or coil we affix a cup-like tuft of buff-colored zephyr worsted-work, having the end of the skein projecting a little higher than the rim, and covered with the same material. Now, from just below the base of the cup-like tuft, let us encase the white coil tightly down to where its threads fray out; let this cylindrical case be of a dark-brown color, and leathery aspect, and ornamented with little starry knobs or warts, like raised embroidery—and then, so far as form is concerned, you have the Hyalonema, or glass-sponge of Japan.
It thus appears from the above that the structure has three parts—the buff-colored mass at one end, the long shaft of white threads, and the star-embossed case which envelops the axis or shaft. Now, what
Japanese Drawings of Hyalonema Sieboldi. (The artist, not knowing the facts in the case, has figured them in wrong position. Compare with Figure 1.)
is the material nature of each part? There is no difficulty about the buff-colored mass, in form like a cup. It has the spicules, and the sarcode, which characterize the sponge-flesh. The axis or coil is of pure translucent silex, like white threads of glass. The surrounding sheath, with the starry prominences, is of a horny or keratose material, much like the stems of the sea-fans, and it is a curious fact that this horn-like sheath is coated with a fine silicious powder, just as it would look if made of India-rubber, and while in the soft, adhesive condition dusted over with fine sand. With so much told, we are prepared for the curious scientific history of this interesting object, which bears a number of popular names, such as Glass-Plant, Glass-Coral, Glass-Rope, etc.
When the scientific men of Europe first made acquaintance with it, this object was an enigma, and for years the subject of much learned controversy. In 1835, some specimens, brought by the traveller Von Siebold, received special study by Dr. John E. Gray, of the British Museum, who named the object Hyalonema Sieboldi. On one point, to use a legal phrase, "each and every" of these learned men literally lost his head when studying this apparent abnormal nondescript; for they all alike stood the specimens on their heads, that is, they placed them, for study, theoretically upside down, namely, with the conical sponge heads, or masses, downward, and of course the coils of silica standing up. It must have been that the Japs themselves started this notion, in honest ignorance, as I believe; for in some natural-history engravings, done by native artists, which are now before me, these objects are portrayed, with the thread-like ends upward, and the sponge mass downward, and as if adhering to something (Fig. 2). This is curious, as the Japanese exhibit in their drawings a closeness in the observation of details that is almost scientific. Dr. Gray's position made the sponge to grow on some object, or on the bed of the sea, and out of the sponge-mass so adhering, like a glass brush standing on its handle, and spreading out in the water, grew the zoophyte, as he regarded the silicious whisp, and its bark-like envelop. Now, among the polyps, known as Alcyonarians, is the Gorgonia, or Sea-fan, which has an axis of a horn-like nature, and a crust of lime; so he made of this polyp, which he supposed constructed the axis and the case, an Alcyonarian, allied to those polyps which build the Sea-fans. But the difficulty was that, instead of a centre or core of keratose, with an
Euplectella Speciosa. The Venus Flower-Basket: A Glass Sponge. That on the right is a portion of the natural size, intended to show the lace-like meshes. The full figure is about half the natural size.
envelop of lime, this had a core or axis of silica, and a bark of keratose. According to Dr. Gray, the Hyalonerna was really two animals, namely, the polyp, represented by the glass coil, and its horny crust; and the sponge, represented by the conical spicular mass, which as a new species he named Carteria.
Prof. Milne-Edwards, in 1857, described the sponge-mass and the glass-rope as but one animal, and "degraded the zoophyte to the rank of an incrusting parasite."
In 1859 appeared the magnificent work of Dr. Brandt, of St. Petersburg, on the Hyalonema. Now, the tables are completely turned. The silicious rope, and its warty bark, are declared to be parts of a polyp, and the sponge is announced as the parasite!—"attaching itself to the polyp, gradually penetrating its silicious axis, and finally killing it." Poor, innocent sponge! Even at the risk of being unparliamentary, we rise to brand that statement as a libel on the sponge.
In 1860 appeared the elaborate memoir on the Hyalonerna by Prof. Max Schultze, of Bonn. He describes the glass-coil and the sponge-mass as belonging to one and the same animal structure. The warty crust, or case, he refers to a distinct animal, a polyp to which he gives the name Palythoa fatua. Schultze, however, makes the polyp a "commensal" with the sponge; that is, they both live at the same table, which means that the sponge, by its ciliary action, has to supply food for both. Schultze's exposition is the generally accepted one. His idea of commensalism, however, the present writer cannot accept. Nor can he accept Milne-Edward's degradation of the zoophyte to a parasite. But want of room will not permit a statement here of the reasons of his disbelief.
The curious fact made clear is that, through all these years of earnest investigation, Hyalonerna was studied upside-down, until Prof. Lovén published his ingenious paper (in 1867, we think), in which, by a little stalked pyriform deep-sea sponge, he demonstrated the true position or attitude in life of the Hyalonerna. In 1870 Prof. Joseph Leidy attained the same conviction from a different line of argument. It was pretty much as if one should ask, "Should a house stand on its chimney?" Says Dr. Leidy: "It has occurred to me that the sponge-mass, in its natural position, was uppermost, and was moored by its glassy cable to the sea-bottom; this opinion is founded on the circumstance that in sponges generally the large oscules from which flow the currents of effete water are uppermost." In fact, these glassy threads, at their lower extremities, spread out in a spiral manner, much like the spray from a turbine water-wheel, and, thus penetrating the mud, afford a good anchorage. This mooring is greatly helped, too, by the peculiar structure of these long silicious needles. These needles, or glassy threads, are, in the body of the fascicle, or skein, cylindrical, and smooth; but, toward their extremities, they are rugose, having almost imbricating rings. Beheld for the first time under the microscope, its sight recalled the appearance of the hairs of a hat. I have convinced myself that this is the functional intention of the frayed end of the fascicle, by a careful examination of a suite of specimens obtained for me at Enosima, Japan, by Prof. Griffis, of the Imperial College at Yeddo.
But the deep-sea dredging described in Dr. Thompson's book sheds much light on the Hyalonema. Says the writer: "When we trace its development, the coil loses its mystery. In two or three hauls we got them in every subsequent stage—beautiful little pear-shaped things, a centimetre long, with a single osculum at the top, and the whisp like a small brush. At this stage the Palythoa is usually absent, but, when the body of the sponge has attained 15 mm. or so in length, very generally a little pink tubercle may be detected at the point of junction between the sponge-body and the coil, the germ of the first polyp."
Pheronema Annæ. Half the natural size. A glass-sponge, obtained at Santa Cruz, W. I.
Allusion has been made to the ingenious manipulation of these glass-sponges by the Japanese. Says Dr. Hadlow, then in Japan: "We sometimes meet with portions of the glass coil most ingeniously attached to and grouped with corals, shells, and other marine products. . . . Such arrangements are entirely artificial, notwithstanding that they are often so artistically done as to have a most deceptively natural appearance." The prettiest specimen of Hyalonema the writer ever saw, one worthy to be called unique, was a clever put-up job. Even to a part of the polyp encasement, from one end to the other, it was put together much as we have seen some fraudulent bird-stuffers put into the tail, wings, and even the crown of the head, feathers from other birds.
Hyalonema was the first of the glass-sponges known to science. It came among the savants as an anomaly of animal structure. Soon after appeared the Venus's Flower-Basket, the peerless beauty among the glass-sponges. In two remarkable respects it resembled its predecessor. Like Hyalonema, it was moored to the sea-bottom by glassy threads; and, like the pretty Glass-Rope Sponge, it made its début in scientific society standing on its head! It was actually so figured by Dr. Owen, its original describer, in the "Zoological Transactions of London." The name by which it is now known is well deserved by an object so lovely—Euplectella speciosa. The first of these words means well-woven, while the second intensifies the first, so that the meaning really is, the specially beautiful, well-woven (Fig. 3.)It is almost hopeless to attempt a description of Euplectella in words. Nor has any artist yet done justice with his pencil to the delicate fabric. The first specimen that reached England, and which for a long time was the only one known, was purchased by William J. Broderip, for the sum of $150 in gold. Says Prof. Owen: "Mr. Cuming has intrusted to me for description one of the most singular and beautiful, as well as the rarest of the marine productions." Euplectella is in form a cornucopia, at the lower end about an inch in diameter, and in good specimens, after making a graceful curve, terminating at top in a width of nearly two inches. This part has a cover with a frilled edge, which, in a complete specimen, projects about a fourth of an inch over the sides. The bottom, or smaller end, is encompassed with a dense ruff of glass threads, so delicately white, flexible, and fine, that they look like a tuft of floss-silk. This muff-like surrounding is sunk into the deep-sea ooze, the fibres pointing up, which, though effectual, is certainly an odd way of mooring itself. In this manner this sponge is, when living, in a perpetual bath of mud. Like Hyalonema, our Euplectella is an anchoring sponge. Venus's Flower-Basket looks like a structure made of spun-glass; and so fragile that one hesitates to take it into the hands. It is wonderfully light—reminding, in this respect, of the skeleton or phantom flowers sometimes seen under glass. But Euplectella, although really so delicate, is quite strong. The threads which make up this fabric of woven
Rossella Velata, natural size. A glass-sponge dredged off the Strait of Gibraltar in 651 fathoms.
glass are so flexible that a body is led to wonder if this is like the product of that lost art. To us it seems doubtful whether any woven glass, the product of art, can quite affect the singular lustre that belongs to these silicious threads spun from Nature's distaff. Each thread, although of pure silica, and solid, is really composed of a series of concentric tubes or cylinders, as if spun on a central thread or core. The effect, as respects the light, is not easily described. As the threads are composed of pure silica, one might suppose that they would be transparent, as a film of pure white glass of equal thickness. Such is not the fact. They are translucent, and have just an appreciable tint of the opal. It is this that imparts to Euplectella that softness of aspect which has been called "a delicate satiny lustre." To us the term opalescent seems better. We have a specimen which, in a good light, shows the play of colors that frozen crispy snow does in the moonlight.
As to the idea "well-woven," which the name contains, the fabric really seems to have its web and its woof. There are long threads that traverse the whole length; and there are others that cross and interlace, or, more correctly, interweave. And, what no loom of human invention has ever done, this lowly weaver makes the fabric as it progresses take on the most quaintly little flounces with the most delicate frilled edges imaginable; and all arranged in such charming grace and ease—not in parallel circles, like hoops on a barrel, but in tasteful, easy-flowing curves. In the configuration of the innumerable forms of structure, Nature, as she ascends in the grade of her work, almost abandons her parallels in the outlining and ornamentation of her constituted things. In the mineral province the structure of crystals shows her delight in parallel, straight lines. The curve is a rarity there. But in organic forms the curve is the rule, and the straight line is the exception. The lace-like structure of the Euplectella is so aerial a fabric, and so quaintly graceful, and, as one might say, so deftly done in the putting together, that any embroidery would seem in the comparison bungling. Enflounced in its own tiny, crispy frills, there is an air of improvised beauty. And there is a flavor of rank in the almost grotesque hint thrown out by the sometimes queer sort of relief afforded in this excess of elegance by a dash of chevron-work.
Euplectella is chiefly got from the Philippine Islands. The natives have their own notions, it seems, about this marvellous object. They will tell you that this beautiful sponge is found in pairs, and that they are the work of little crabs, who, they believe, build these houses while living inside them. It is a remarkable fact that generally in these glass cornucopias, as if they were cages, a pair of little crabs dwell together. How they ever got inside nobody knows. Can it be that they are silly enough to wall themselves up in this limbo of silica? Not they, although they do have nippers and thumbs. A much lowlier creature, fingerless, and for that matter organless, up-rears these fairy structures. However, the fact is indisputable. There they are, incased in glass, and beyond the possibility of deliverance. Were these little folks communicative, and not so crabbed, one might ask if they acted out the moral of the adage about people who live in glass houses. There is little doubt that this imprisonment is voluntary. We think these crabs are true commensals. Whether welcome or not, they always eat at the Euplectella's table. Lest we should seem to be muddling the work of the systematists, we would be understood metaphorically, when stating our positive conviction that these crabs are sponges from their very birth.
A new glass-sponge, obtained from the island of Santa Cruz, W. I., is described by Prof. Joseph Leidy, in the American Naturalist for March, 1870. Some description of it had already been given elsewhere. Its form is seen in Fig. 4. It will be remembered that the glass-rope sponge had one fascicle or bundle of glass threads. This sponge has at least twenty of these bundles, each about two inches long. These also are of silicious threads, and have the appearance of "tufts of blond human hair." It would not be strange should a lady naturalist liken them to skeins of cuir-color zephyr worsted; for, queer as this may seem, such would be an unconscious guessing of the name which this new sponge has received. Pheronema means the skein-bearer. "In honor of his wife," Prof. Leidy "has dedicated the species under the name of Pheronema Annæ.
The names of this trio of wonderful sponges are, it will be seen, expressive, euphonious, and picturesque––Hyalonema, the glass, or hyalene skein—Euplectella, the accomplished weaver—Pheronema, the skein-bearer.
A Group of United Spicules in Pheronema.
And now, like wresting jewels from the land of Ind, the naturalist has found that these inimitable gems are of many kinds and abundant, but locked up in the hitherto unapproachable coffers of the deep sea. First, the Norwegian scientist invaded this domain, and bore off amazing treasures. Then the Americans tried these great depths, and brought up gems that amazed the eyes of the naturalist. Then came the English expeditions, tolling the ocean treasury at the astounding depth of 15,000 feet! It is now found that the congenial home of the glass-sponges is the emphatically deep water. There are precious stores of exquisite forms and structures, that have never been seen by any except their Creator. One of these, described in Dr. Thompson's book, which was obtained during the cruise of the Lightning, is named in honor of M. Holten, the Danish governor at Faroe, and Prof. Carpenter—hence the appellation Holtenia Carpenteri. It is about nine inches long, and three and a half inches wide. The body of this glass-sponge is of an oval, or egg-shaped form. At the bottom is a great mass of fine silicious threads, like white hairs, wadded together like a mop. These are its anchoring threads. There is a crater, or oscular opening at top, about three-fourths of an inch wide, around which, on the outside, short threads of silica stand out, not unlike a beard. Thus the upper part of the sponge might be likened to a bird's-nest. Hence the Setubal deep-sea shark-fishers, who sometimes bring them up from great depths with threads of Hyalonema on their fishing-lines, call them "sea-nests." The spicules are arranged in little stellate groups, the effect being that the entire surface of the sponge has an ornamentation of stars.
We can mention but one more of these singular beings. This is the Rossella velata, Fig. 5. And here we will borrow Dr. Thompson's own words: "On August 30, 1870, Mr. Gwyn Jeffreys dredged in 651 fathoms in the Atlantic off the mouth of the strait of Gibraltar an exquisite sponge, resembling Holtenia in its general appearance, but differing from it in the singular and beautiful character of having a delicate outer veil, about a centimetre from the surface of the sponge, formed by the interlacing of the four secondary rays of large five-rayed spicules, which send their long shafts from that point vertically into the sponge-body. The surface of the sponge is formed of a network of large five-radiate spicules, arranged very much as in Holtenia; but the spicules of the sarcode—the small spicules which are embedded in the living sponge-jelly—are of totally different form. A single large 'osculum' opens, as in Holtenia, at the top of the sponge, but instead of forming a cup uniformly lined with a netted membrane, the oscular cavity divides at the bottom into a number of branching passages, as in Pheronema Annæ, described by Dr. Leidy. The spicules of the 'beard' are more rigid and thicker than those of Holtenia, and scattered among them are some very large four-barbed grappling-hooks." Such is the capital description of the learned naturalist. To be sure, some old "salt" would be more laconic; for he doubtless would tell you that it was like a pine-apple, with the crown and its core removed.
We have tried to make plain what is meant by sponge-flesh, for which the word sarcode is used. It should be understood that this sarcode, which is a semi-fluid substance, is simply held to the mesh-like skeleton and to itself by the interlacing of tiny needles of flint, called spicules, so that the albuminous-like flesh is really felted together. From the sponge of the toilet this sarcode and its spicules have been all removed. The interesting fact is that, while these spicules are arranged in different patterns, many being made to radiate like stars, no two species have the same pattern. Look at Fig. 6, which represents the spicules of Pheronema. It looks as if
Section of the Outer Wall of Ventriculites Simplex, showing the structure of the silicious network. Magnified 50 times.
the series were united together to make an irregular star. Now, one of these needles sticks perpendicularly into the sarcode, leaving the other rays to spread out in a plane, to which the one that serves as a spike is perpendicular. One might liken it to a parasol without its silk covering—the handle in the hand is the spike, and the steel ribs
Extremity of a Mooring-thread of Pheronema, showing the notched sides and the anchor-flukes at the end. Greatly magnified.
spread out will represent the silicious rays, or spicules. At a little distance from this penetrating needle, or spike, the needle of another of these irregular stars pierces the sarcode. Of consequence, the radiating needles, or spicules, of each one of these irregular stars lock into the similar spicules of the adjoining star, and so on for the entire mass, until it has the effect of felt; with this great difference, however—so regular is this natural felting of the sponge-flesh—that the whole mass is spiculated or laid out in quite regular and pretty patterns; and such is the uniformity of pattern for each kind that they actually mark the difference of species. As evidence of this regularity and beauty, look at the engraving of the spicular pattern of a fossil glass-sponge (Fig. 7). Now, it should be observed of the sponges which we have given in detail, that their spicules are arranged on a six-rayed plan, or, as sometimes expressed, hexradiate. Accordingly, Prof. Oscar Schmidt has "defined the group as a family under the name Hexactinellidæ."
Ventriculites Simplex.—A fossil sponge, one and a half the natural size, showing the surface ornamented by a regular arrangement of ventricles. (See Fig. 10.)
Many of these glass-sponges have the habit of mooring themselves by their silicious threads, and on this account are called "anchoring sponges." Though acting in this matter on one general principle, yet they have diversities of ways in carrying out this law of their nature. Hyalonema, the glass-rope sponge, plunges its long threads down into the mud, and then spreads them out like a brush. These threads have a ringed structure, so that each one has an individual hold, or purchase, like that of a screw. Venus's Flower-Basket has the small end of the cornucopia plunged deeply into the sea-ooze, and from its extreme end threads go out with an upward and outward curve. Thus the mud rests upon them on the inside of the curves, and holds the dish-shaped tuft of fibres down. Pheronema has its threads near the extremities marked by projecting notches, while at the very extremity it is actually anchor-shaped, as shown by a thread magnified (Fig. 8). Holtenia has a great mop of fine roots, like what is often seen when changing a plant from one flower-pot to another. Rossella has a great outlay of mooring-threads, with frequently a line quadrate-barbed at its extremity. This is well shown in Fig. 5. These lines have actually at the bottom a four-hooked grapnel.
A very interesting fact is this: The study of these Hexactinellidæ has made clear as light the structure and character of the curious flinty fossils obtained from the cretaceous formation, and known as Ventriculites. Fig. 9 shows one of these fossils, and Fig. 10 shows its beautiful spicular structure. It is now plain that they were glass-sponges, and also belonged to the family Hexactinellidæ; while the deep-sea dredging, as it brings up these so long-concealed witnesses, is proving that our notion, that the cretacean forms of life belonged wholly to the great past, needs careful revision; for it may be that this ante-biotic theory is not quite correct.
Outer Surface of the Fossil Sponge. Ventriculites Simplex, magnified four times, showing the ventricles which make the outer ornament. (See Fig. 9.)
And there are many strange and also beautiful forms of life that are the companions of these deep-sea sponges. Yes, and even almost formless conditions of life are there. A substance like albumen, a sort of protoplasm, spreads over the broad acres of the sea-bottom. Perhaps it is the manna which Providence has given to these wonderful creatures that occupy these deserts beneath the sea. Certain it is that, in two senses, the dredger is plunging into the profoundest physical problems. How precious, then, is every grain of mud obtained from such depths! Hence the careful treatment it receives when brought on deck. Fig. 11 shows the sieves used. The whole nest of four is used at once. Some of the mud is put into the top one, which has large meshes, these meshes decreasing in size, so that the smallest are in the sieve at the bottom. The whole are set in a deep tub of sea-water. There is to be no turning round of the sieves, as that would break or bruise some of the frail organisms. Taking hold of the handles of the bottom sieve, the whole nest is lifted up and down with a gentle churning motion; and, when the mud is all passed through, the objects are tenderly removed to jars of sea-water. A bone forceps is used for this purpose.
The Sieves used in separating the Contents of the Dredge in Deep-sea Dredging.
What a wonderful, yea, fascinating thing, then, is this lovely glass-sponge! It is amazing that a creature so simple, that it has been called structureless, should surpass all other organisms in its capacity of rearing exquisite fabrics. And, now that we have had time to sober down a little in our raptures over its structural beauty, and, so to speak––like one that has passed from the pleasant contemplations of art to the graver meditations of philosophy––to listen with composure to its deeper teaching, we find it casting new light upon the inquiries of Science––even lifting a corner of the veil of the covered past. So little, until lately, did we know about the glass-sponge, that we were like the purblind prehistoric man working patiently at his flint nodule to fashion it into an implement for use, little dreaming that some glass-sponge had been the ancient eliminator and conservator of the solvent silex of the sea, and had, through subsequent geologic action, preserved its skeleton for the service of that ruder artisan. What a freight of precious knowledge will that be, when the good ship Challenger shall have returned from her four years' dredging around the world, among that newly-opened "Abyssal Fauna," whose province covers 140,000,000 square miles beneath the blue mantle of "the myriad smiling sea!"